From: Peter Maydell <peter.maydell@linaro.org>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Thomas Lendacky <Thomas.Lendacky@amd.com>,
Ashish Kalra <Ashish.Kalra@amd.com>,
Brijesh Singh <brijesh.singh@amd.com>,
Eduardo Habkost <ehabkost@redhat.com>,
kvm-devel <kvm@vger.kernel.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Markus Armbruster <armbru@redhat.com>,
QEMU Developers <qemu-devel@nongnu.org>,
ssg.sos.patches@amd.com, Paolo Bonzini <pbonzini@redhat.com>,
Richard Henderson <rth@twiddle.net>
Subject: Re: [PATCH 01/11] memattrs: add debug attribute
Date: Tue, 1 Dec 2020 11:56:26 +0000 [thread overview]
Message-ID: <CAFEAcA_cdixD7jvu68snUU=PN2xQow1W2goKjshfdF9jGb2dBQ@mail.gmail.com> (raw)
In-Reply-To: <20201201115047.GA15055@work-vm>
On Tue, 1 Dec 2020 at 11:51, Dr. David Alan Gilbert <dgilbert@redhat.com> wrote:
>
> * Peter Maydell (peter.maydell@linaro.org) wrote:
> > On Mon, 16 Nov 2020 at 19:28, Ashish Kalra <Ashish.Kalra@amd.com> wrote:
> > >
> > > From: Brijesh Singh <brijesh.singh@amd.com>
> > >
> > > From: Brijesh Singh <brijesh.singh@amd.com>
> > >
> > > Extend the MemTxAttrs to include a 'debug' flag. The flag can be used as
> > > general indicator that operation was triggered by the debugger.
> > >
> > > A subsequent patch will set the debug=1 when issuing a memory access
> > > from the gdbstub or HMP commands. This is a prerequisite to support
> > > debugging an encrypted guest. When a request with debug=1 is seen, the
> > > encryption APIs will be used to access the guest memory.
> >
> > So, what counts as "debug" here, and why are debug requests
> > special? If "debug=1" means "can actually get at the guest memory",
> > why wouldn't every device model want to use it?
>
> SEV has a flag that the guest-owner can set on a VM to enable debug;
> it's rare for it to be enabled; so it's not suitable for use by normal
> devices. It's only there for debug if the guest owner allows you to.
So if I do a memory transaction with debug=1 then I should expect
that it might come back with a failure status (meaning "this VM
doesn't permit debug") and I should handle that error ?
thanks
-- PMM
next prev parent reply other threads:[~2020-12-01 11:58 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-16 18:48 [PATCH 00/11] Add QEMU debug support for SEV guests Ashish Kalra
2020-11-16 18:48 ` [PATCH 01/11] memattrs: add debug attribute Ashish Kalra
2020-12-01 11:03 ` Dr. David Alan Gilbert
2020-12-01 11:43 ` Peter Maydell
2020-12-01 11:50 ` Dr. David Alan Gilbert
2020-12-01 11:56 ` Peter Maydell [this message]
2020-12-01 18:57 ` Dr. David Alan Gilbert
2020-11-16 18:49 ` [PATCH 02/11] exec: Add new MemoryDebugOps Ashish Kalra
2020-12-01 11:37 ` Dr. David Alan Gilbert
2020-12-01 11:48 ` Peter Maydell
2020-12-01 14:27 ` Ashish Kalra
2020-12-01 14:38 ` Peter Maydell
2020-12-01 14:49 ` Ashish Kalra
2020-11-16 18:49 ` [PATCH 03/11] exec: add ram_debug_ops support Ashish Kalra
2020-12-01 12:08 ` Peter Maydell
2020-12-01 14:43 ` Ashish Kalra
2020-11-16 18:50 ` [PATCH 04/11] exec: Add address_space_read and address_space_write debug helpers Ashish Kalra
2020-11-16 18:51 ` [PATCH 05/11] exec: add debug version of physical memory read and write API Ashish Kalra
2020-11-24 5:42 ` Dov Murik
2020-11-16 18:51 ` [PATCH 06/11] monitor/i386: use debug APIs when accessing guest memory Ashish Kalra
2020-12-01 11:54 ` Peter Maydell
2020-12-01 12:05 ` Peter Maydell
2020-11-16 18:51 ` [PATCH 07/11] kvm: introduce debug memory encryption API Ashish Kalra
2020-11-16 18:52 ` [PATCH 08/11] sev/i386: add debug encrypt and decrypt commands Ashish Kalra
2020-11-16 18:52 ` [PATCH 09/11] hw/i386: set ram_debug_ops when memory encryption is enabled Ashish Kalra
2020-11-16 18:52 ` [PATCH 10/11] sev/i386: add SEV specific MemoryDebugOps Ashish Kalra
2020-11-16 18:53 ` [PATCH 11/11] target/i386: clear C-bit when walking SEV guest page table Ashish Kalra
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAFEAcA_cdixD7jvu68snUU=PN2xQow1W2goKjshfdF9jGb2dBQ@mail.gmail.com' \
--to=peter.maydell@linaro.org \
--cc=Ashish.Kalra@amd.com \
--cc=Thomas.Lendacky@amd.com \
--cc=armbru@redhat.com \
--cc=brijesh.singh@amd.com \
--cc=dgilbert@redhat.com \
--cc=ehabkost@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=mst@redhat.com \
--cc=mtosatti@redhat.com \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=rth@twiddle.net \
--cc=ssg.sos.patches@amd.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).